This invention relates generally to vacuum systems and particularly relates to a vacuum pump of the type having a venturi tube and associated equipment such as a desoldering instrument, vacuum clamping fixtures, a power cylinder and vacuum operated suction cups.
Many types of vacuum pumps are known in the art. A very efficient type of vacuum pump is operated by a supply of compressed gas such as air. The compressed air is caused to flow through a venturi tube which creates a reduced pressure at its throat to provide the desired vacuum. Such a pump has been disclosed in the patent to Thurman et al. U.S. Pat. No. 1,014,729. The pump includes a valve which is designed to create a steady state according to a varying vacuum load. Thus the valve will control the amount of compressed air fed into the pump. Accordingly, the valve is either completely turned off or remains partially open during operation to control the flow of compressed air. This is effected by utilizing two preset limit valves.
The disadvantage of such a system is that it requires a continuous supply of compressed gas, thus wasting the compressed air. As a result, this type of pump is not suited to provide a compact, portable system including a compressed air supply and a vacuum pump. A somewhat similar vacuum pump has been disclosed in the patent to Des Rocher U.S. Pat. No. 1,187,719. In other words, in this pump the valve is never completely on or completely off. The pump disclosed in the patent to Lung U.S. Pat. No. 2,457,388 is never completely closed.
It is accordingly an object of the present invention to provide a vacuum system including a vacuum pump where the vacuum is generated by a venturi tube and which is characterized by an on-off operation.
A further object of the present invention is to provide a vacuum pump of the type discussed capable of maintaining a reduced pressure between two preset limits whereby the pump begins to operate when the pressure exceeds a certain upper limit and stops when the pressure has reached a certain lower limit.
Another object of the present invention is to provide a vacuum system as previously discussed which is small and efficient and which can be operated by a portable compressed gas supply along with a portable pump.
Still a further object of the present invention is to provide a vacuum system as previously described which includes various attachments such, for example, as a vacuum desoldering tool, a power cylinder, clamping fixtures and vacuum operated suction cups.
Still another object of the present invention is to provide a vacuum system including a vacuum pump and a vacuum operated desoldering tool or a desoldering attachment for a soldering instrument.
Yet a further object of the present invention is to provide a vacuum system including a vacuum pump and a power cylinder having a single piston which is not spring biased and a single connection to a vacuum and a compressed air supply.
Yet another object of the present invention is to provide a vacuum system including a vacuum pump and a pair of clamping fixtures for clamping a component and which may be moved on a work bench and secured thereto by the action of the vacuum.
Yet a further object of the present invention is to provide a vacuum system including a vacuum pump and vacuum operated suction cups which may be utilized for permitting a worker to walk on slippery surfaces and which are controlled by a motion sensor.